Sulfur-linked linear alkyl vicinal disulfates

ABSTRACT

DETERGENT ACTIVE MATERIALS WHICH ARE EFFECTIVE IN THE ABSENCE OF PHOSPHATE BUILDERS COMPRISE SULFUR-LINKED LINEAR ALKYL VICINAL DISULFATES OF THE FORMULA:   R-CH(-R1)-Y-CH2-CH(-O-SO3-X)-CH2-O-SO3-X   IN WHICH Y IS   -S-, -SO-, OR -SO2-   R AND R1 ARE HYDROGEN OR ALKYL RADICALS HAVING A TOTAL OF FROM 9 TO 23 CARBON ATOMS, AND X IS HYDROGEN OR A WATER-SOLUBLE SALT-FORMING CATION.

United States Patent 3,651,119 SULFUR-LINKED LINEAR ALKYL VICINALDISULFATES Robert G. Anderson, San Rafael, Califi, assignor to ChevronResearch Company, San Francisco, Calif. No Drawing. Filed Aug. 5, 1970,Ser. No. 62,233 Int. Cl. C07c 141/02 US. Cl. 260-458 4 Claims ABSTRACTOF THE DISCLOSURE Detergent active materials which are effective in theabsence of phosphate builders comprise sulfur-linked linear alkylvicinal disulfates of the formula:

R and R are hydrogen or alkyl radicals having a total of from 9 to 23carbon atoms, and X is hydrogen or a water-soluble salt-forming cation.

BACKGROUND OF THE INVENTION This invention is concerned withsulfur-linked linear alkyl vicinal disulfates which are effective asheavy duty detergent active material.

Increased concern over water pollution has produced significant changesin household detergents. Initially, major emphasis has been placed onproducing biodegradable surface-active components for detergents. Theshift to linear surface-active materials, including linear alkylbenzenesulfonate (LAS) and alpha-olefin sulfonates, etc., has reduced pollutionattributed to nonbiodegradability.

However, the above-mentioned surface-active materials are inadequate interms of soil removal in the absence of phosphate builders. Increasingevidence appears to indicate that phosphates contribute to the growth ofalgae in the nations streams and lakes. This algae growth poses aserious pollution threat to the maintenance of clear, good domestic:water supplies.

Consequently, there has developed a need for detergent active materialswhich will function successfully in the absence of phosphate builders.Recently, certain nonphosphate building materials have been proposed asreplacements for the phosphates. Thus, materials such as the polysodiumsalts of nitrilotriacetic acid, ethylene diamine tetraacetic acid,copolymers of ethylene and maleic acid, and similar polycarboxylicmaterials have been proposed as builders. These materials, however, whenemployed with conventional detergent actives such as LAS, have, for onereason or another, not proved to be quite as effective as phosphates indetergent formulations. For example, some of the materials have provento be insufiiciently biodegradable to meet present and anticipatedrequirements.

It is therefore desirable to provide compounds which are effective asdetergent active materials in the absence of phosphate builders and arealso sufficiently biodegradable that their use results in contributingneither foam producers nor phosphates to the water supply.

SUMMARY OF THE INVENTION Effective heavy duty detergent compositionswhich may Patented Mar. 21, 1972 be formulated without the necessity ofphosphate builders are provided. These formulations employ as detergentactive materials sulfur-linked linear alkyl vicinal disulfates of theformula:

in which Y is R and R are hydrogen or alkyl radicals having a total offrom 9 to 23 carbon atoms, and X is hydrogen or a water-solublesalt-forming cation. In a preferred form Yis and X is an alkali metalcation. It is also preferred that the sum of the carbon atoms in R and Rbe in the range of 13 to 19 carbon atoms.

The compounds of this invention do not require the presence of aphosphate builder to achieve good detergency. They achieve excellentdetergency with such materials as the sodium salts of nitrilotriaceticacid and polycarboxylates such as ethylene-maleic anhydride copolymer.The materials, however, may be employed in the absence of any builder.

DESCRIPTION OF PREFERRED EMBODIMENTS The salt-forming cation X may beany of numerous materials such as alkali metal, alkaline earth metal,ammonium, or various organic cations. Examples of suitable organiccations include amino materials such as those of the followingstructure:

NH HOH CH OH) 2 or HN+ (CH CH OH) 3 The alkali metal cations arepreferred, and sodium ions are particularly preferred.

The alkyl groups represented by R and R are, as previously noted,linear, although the presence of a random methyl radical upon the linearchain, for example, may not adversely affect the performance of thecompound. Alkyl radicals representative of R and R include hexadecyl,heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, and docosyl.Heptadecyl, octadecyl, nonadecyl, eicosyl, and heneicosyl groups arepreferred. In a preferred form the materials are formed by the reactionof thioglycerol wtih an alpha olefin and thus one or the other of R andR will be hydrogen.

The detergent active compounds of this invention are preferably preparedby reacting a linear monoolefin, preferably an alpha olefin, withthioglycerol giving a compound having two vicinal hydroxy groups. Thehydroxy groups are then sulfated by conventional techniques giving acompound containing two sulfate groups and a sulfide linkage in thebackbone. This compound, while being an adequate detergent, is sensitiveto bleaching and in the preferred embodiment the sulfide prior tosulfation is oxidized to a sulfoxide or a sulfone or a mixture thereof.The products then obtained by sulfation are excellent detergents and arebleach stable.

The reaction of the olefin and the thioglycerol is accomplished bysimply heating the materials together followed by recrystallization fromconventional solvents such as ethanol or benzene. The sulfation of thedioxy compound is efiected by conventional sulfation techniquesemploying sulfur trioxide, chlorosulfonic acid, oleum,

3 sulfuric acid, etc., in a ratio of at least 2 mols of sulfatingagent-per mol of diol. Ratios of from 2 to 10 are preferred. When it isdesired to oxidize the sulfide group prior to sulfation, this isaccomplished again by conventional techniques employing as oxidizingagents hydrogen peroxide, metal hypohalites, etc.

The following examples illustrate the preparation of the compounds ofthis invention.

EXAMPLE 1 Addition of thioglycerol to l-hexadecene A 500 ml. flask wascharged with 112 g. (0.5 mol) of l-hexadecene, 71.5 g. (0.6 mol) ofthioglycerol, and 100 ml. of ethanol. The mixture was placed upon a hotplate and heated overnight at 50-70 C. The mixture, originally in twolayers, had become homogenous. It was allowed to cool to roomtemperature and then further cooled with ice. The solid product in theflask was removed by filtration and recrystallized from ethanol. Theproduct was dried in a 50 C. oven overnight and gave a yield of 126 g.of a white solid which melted at 71-72 C. and by IR analysis showed twotypes of -OH absorption and no remaining olefin bonds.

EXAMPLE 2 Addition of thioglycerol to l-eicosene The procedure ofExample 1 was followed employing 140 g. (0.5 mol) of l-eicosene insteadof hexadecene. After recrystallization from ethanol there was obtained166.6 g. (85.9% yield) of a white solid which showed by IR analysis twotypes of OH absorption and the presence of a small amount of alphaolefin. The product was recrystallized from benzene to give a whitesolid, melting point 8283.5 C., an IR analysis of which showed noremaining olefin bonds.

EXAMPLE 3 Addition of thioglycerol to l-docosene The procedure ofExample 1 was followed employing 154 g. (0.5 mol) of l-docosene. Theproduct recrystallized from benzene was 183 g. (88% yield) of a whitesolid having a melting point of 87-88 C.

EXAMPLE 4 Oxidation of eicosene-thioglycerol adduct 15.1 g. (0.039 mol)of the product of Example 2 and 60 ml. of glacial acetic acid wereplaced in a 125 ml. flask equipped with a magnetic stirrer. Athermometer was inserted and 10.5 ml. (0.084 mol) of 30.6% H was addedslowly and with stirring. The maximum temperature reached without theapplication of external heat was 50 C. The temperature was raised to 80C. and maintained for 1% hours. The mixture was cooled in ice and theproduct collected by suction. The white solid thus obtained wasrecrystallized from benzene to give 14.7 g. (90.0% yield) of product aswhite needles, melting point 112-l13 C., whose IR spectra showed astrong band at 1120 cm.- (-SO and nothing at about 1000 cmr (--SO-).

EXAMPLE 5 lSulfation of oxidized hexadecene-thioglycerol adduct with50;,

276 mg. (0.6 mmol) of a sulfone-containing material prepared accordingto the procedure of Example 4 from the product of Example 1 was placedin a 100 ml. stoppered graduated cylinder containing ml. of CCL, and amagnetic stirring bar. The mass was heated to dissolve, then stirred andplaced in an ice bath. The precipitate was uniformly fine. Afterflushing with N 0.1 ml. of S0 was added dropwise to the cold suspension.The mixture turned yellow and dissolvecLIhe cylinder was removed :fromthe ice and an additional 0.1 ml. of S0 4 was added dropwise. The colordarkened. A 1 ml. sample was titrated with Hyamine showing the presenceof 1.9 sulfate groups per molecule. The CC], was removed from theremainder of the solution, water was carefully added, and the whole wasneutralized to a pH of 10 (pH meter) with NaOH solution.

EXAMPLE 6 Sulfation of sulfoxide-containing-octadecene thioglyceroladduct 0.5 g. of an adduct of l-octadecene with thioglycerol preparedaccording to the procedure of Example 1 and oxidized to contain onesulfoxide group per molecule was placed in a 250 ml. beaker anddissolved in 40 ml. of dry methylene chloride. After cooling the mixtureto 10 C., 1.0 ml. of chlorosulfonic acid was slowly added by submergingthe tip of an eyedropper containing the acid below the surface of thewell agitated solution. The resulting solution was allowed to stand atambient conditions for five minutes. The pH was adjusted to 8-9 withdilute sodium hydroxide. The solvent was removed by gentle warming andthe residue diluted to 10 ml.

EXAMPLE 7 Sulfation of eico'sene-thioglycerol adduct with chlorosulfonicacid A 125 ml. Erlenmeyer flask was charged with 0.5 g. (51.29 mmoles)of the product of Example 2 and 40 ml. of dry diethyl ether. Aftercooling the mixture to 10 C., 1.0 ml. of chlorosulfonic acid was slowlyadded by submerging the tip of an eyedropper containing the acid belowthe surface of the well agitated ether solution. The resulting solutionwas allowed to stand at ambient conditions for five minutes. The pH wasadjusted to 8-9 with dilute sodium hydroxide. The solvent was removed bygentle warming and the residue diluted to ml.

Detergency of the compounds of the present invention is measured bytheir ability to remove natural sebum soil from cotton cloth. By thismethod, small swatches of cloth, soiled by rubbing over face and neck,are washed with test solutions of detergents in a miniature laboratorywasher. The quantity of soil removed by this washing procedure isdetermined by measuring the reflectances of the new cloth, the soiledcloth, and the washed cloth, the results being expressed as percent soilremoval. Because of variations in degree and type of soiling, in waterand in cloth, and other unknown variables, the absolute value of percentsoil removal is not an accurate measure of detergent effectiveness andcannot be used to compare various detergents. Therefore, the art hasdeveloped the method of using relative detergency ratings for comparingdetergent eifectiveness.

The relative detergency value is obtained by comparing and correlatingthe reflectance value results from the test solution with the resultsfrom two defined standard solutions.

The two standard solutions are selected to represent a detergentformulation exhibiting relatively high detersive characteristics and aformulation exhibiting relatively low detersive characteristics.

-By testing experimental solutions against the two standardizedsolutions, using different portions of the same soiled cloth, theresults can be accurately correlated. The two standard solutions wereprepared for the following detergent formulations:

Formulation for the low detersive standard (Control A) Ingredient:Weight percent Formulation for the high detersive standard (Control B)Ingredient: Weight percent The standard exhibiting high-detersivccharacteristics was prepared by dissolving a relatively large amount ofthe above formulation (Control B) (2.0 g.) in 1 liter of 300 p.p.m. hardwater (calculated as calcium carbonate and /3 magnesium carbonate). Thelow detersive standard contained a relative low concentration of theformula (Control A) (1.0 g.) dissolved in 1 liter of 300 p.p.m. water(same basis).

The miniature laboratory washer used was so constructed that the twostandard formulations and two test formulations could he used to washdifferent parts of the same swatch. This arrangement ensured that allfour formulations were working on identical soil (natural facial soil).Relative detergency (RD) values were calculated from soil removals (SR),according to the equation:

Percent SR -Percent. SR A RD=2+4 Percent SR Percent SR m, A

lated with additional compatible ingredients being optionallyincorporated to enhance the detergent properties. Such materials mayinclude but are not limited to anticorrosion, antiredeposition,bleaching and sesquestering agents, and certain organic and inorganicalkali metal and alkaline earth metal salts such as in organic sulfates,carbonates, or borates. Also nonphosphate builders may be included inthe composition. Examples of these builders are the sodium salts ofnitrilotriacetic'acid, ethylene diamine tetraacetic acid, and ethylenemaleic acid copolymers, etc. Also small quantities of phosphate buildersmay be included although, of course, they are no necessary for elfectivedetergency.

While the character of this invention has been described in detail withnumerous examples, this has been done by way of illustration only andwithout limitation of the invention. It will be apparent to thoseskilled in the art that modifications and variations of the illustrativeexamples may be made in the practice of the invention within the scopeof the following claims.

I claim:

1. A compound of the formula:

R and R are hydrogen or alkyl radicals having a total of from 9 to 23carbon atoms, and X is hydrogen or a member of the group consisting ofalkali metal, alkaline earth metal, ammonium, NH +(CH CH OH) and NH+(CHCH OH) cations.

RELATIVE DETERGENOY OF ALKYL VICINAL DISULFATES Relative detergencyratings in 50 p.p.m. 1120' Test materials Sultoxldes Sulfones NTA Carbonatoms Compound tested Cone. cone. in R andgRi 0.1% cone. 0.2% conc. 0.1%cone. 0.2% cone.

The relative detergency rating for linear alkylbenzene sulfonate (LAS)was 2.9 at 0.1% and 3.9 at 0.2% concentration (50 p.p.m. waterhardness). The rating for an LAS (20%)lsodium triphosphate conventionalbuilt detergent was 5.8 at 0.1% and 6.1 at 0.2% concentration p.p.m.water hardness). These materials 'were tested in formulations containing7% sodium silicate, 1% carboxymethylcellulose, 8% water, the indicatedamounts of LAS and phosphate, and sufficient sodium sulfate to give100%.

The sulfur-linked linear alkyl vicinal disulfates may be employed incombination with other detergent active materials. They are particularlyeffective with other dianionic materials, examples of which includelinear alkyl and alkenyl disulfates and disulfonates. A particularlyuseful class of materials for use in detergent active combinations isthat of linear 2-alkenyl or linear 2-alkyl 1,4- butane diol disulfatesin which the alkenyl or alkyl groups contain from 15 to 20 carbon atoms.

In employing the detergent active materials of this invention indetergent compositions, they may be formu- UNITED STATES PATENTS2,645,659 7/ 1953 Morris et al 260-458 X FOREIGN PATENTS 6709714 l/ 1968Netherlands 260-458 LEON ZITVER, Primary Examiner L. B. DE CRESCENTE,Assistant Examiner US. Cl. X.R. 252161

